ENCARDIO-RITE ELECTRONICS PVT. LTD.
A-7, Industrial Estate, Talkatora Road
Lucknow, UP - 226011, India
P: +91 522 2661039-42 | F: + 91 522 2662403
[email protected] | www.encardio.com
INTERNATIONAL: UAE | QATAR | SAUDI ARABIA | BAHRAIN | GREECE | SINGAPORE | BHUTAN
INDIA: LUCKNOW | DELHI | KOLKATA | MUMBAI | CHENNAI | BANGALORE | HYDERABAD | J&K
AN-1501 January 2015
ONLINE MONITORING OF BUILDINGS, MONUMENTS, STRUCTURES & BRIDGES
1 INTRODUCTION
Encardio-rite offers online web based monitoring services for the following:
Safety of existing multiple storey buildings, hotel complexes, corporate offices and buildings of critical
importance
Safety of old and depleted buildings and structures subject to long-term movement or degradation of
materials and monuments/structures of historical importance
Safety of structures (buildings, monuments, bridges, existing tunnels) during nearby construction activity like
construction of Metros, deep excavation for high rise buildings etc.
Safety of buildings and structures in hills and landslide prone areas
2 STRUCTURAL MONITIORING SOLUTIONS
For buildings, structures and bridges etc., it is recommended that Structural Health be continuously monitored to
ensure proper maintenance and safety of man and material. A basic system offered by Encardio-rite that can be
used for most structures essentially consists of the following:
Encardio-rite model ESDL-30MT SDI-12 data logger with in-built tiltmeter mounted at one or more locations
on the structure to measure and log tilt data (ideally at an indoor location or in shade to prevent effect of
large temperature fluctuations on the monitored results). ESDL-30MT is provided with an integral
GSM/GPRS modem for storing and transmitting data to a server with the service provider.
Encardio-rite model EDJ-40V vibrating wire crack meter (with ESVI-01-01 SDI-12 interface box) to monitor
structural cracks
Encardio-rite model EAN-93M-B biaxial tilt meter with integral SDI-12 protocol (at additional locations, if
required)
Crack meters and additional tilt meters can be connected to nearest ESDL-30MT.
Some other surface and subsurface sensor that may be used
depending upon the structure to be monitored and its location
are given below. Subsurface monitoring gives important
information on ground/soil movement which may affect the
stability of the structure.
Encardio-rite model EDS-70V vibrating wire type multiple
point borehole extensometer (with ESVI-01-04 SDI-12
interface box) for monitoring sub-surface settlement and
lateral movement at specified points.
Encardio-rite model ELC-30S resistive strain gage type
centre hole load cell (with ESBI-10 SDI-12 interface box)
for monitoring tension in anchors used for stabilizing the
slope.
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Encardio-rite model EPP-30V vibrating wire piezometer (with ESVI-01-01 or ESVI-10VB SDI-12 interface
box) to monitor sub-surface water level. In case atmospheric pressure is to be monitored, use the model
ESVI-10VB as it has an integral barometric pressure sensor.
Encardio-rite model EAN-52MV vertical in-place inclinometer system with several biaxial probes (with
integral SDI-12 protocol) mounted vertically in a borehole to monitor sub-surface lateral movements around
the structure.
Encardio-rite model ERG-200 tipping bucket rain gage (with ESGI-10 SDI-12 interface).
Encardio-rite model ESDL-30 data logger for the above mentioned sensors, with integral GSM/GPRS
modem for storing and transmitting data to a server. For details refer to data sheet 1216-15 datalogger for
SDI-12 interface sensors
Encardio-rite online web data monitoring service (WDMS) that provides data online (with alarms) to
authorised users at different locations, on their computer/laptops. More details are given in section 3.
NOTE: Data retrieval from datalogger is also possible by directly downloading it on a laptop.
Collapse of a building or bridge is often preceded by change in tilt of affected areas. The above instrumentation
is a standardized low cost system effectively used to online monitor several type of structures to give timely
warning on impending danger. The purpose is to assist and inform owner/designer/contractor/architect about
continued performance of structures under gradual or sudden changes to their state. The main factors affecting
the performance is degradation of structure with age, undue settlement/tilt due to soil conditions or nearby
construction activity, vibrations due to traffic, ground water level, atmospheric conditions and movement of
slopes in hilly areas etc. This may be reflected in abnormal changes in tilt and settlement values.
Data is available online with alarms through Encardio-rite Web Monitoring Services. For buildings and structures
built on a hill or a mountain, this is a good low cost service for monitoring their stability with time. It may give
forewarning of ground movement during rainfalls.
Crack meter
Piezometer
Under pass road
Road - ground level
In-place inclinometer
Anchor bolt load cell
Tilt meter
Borehole
extensometer
Automatic datalogger
Datalogger with inside tilt meter
Strut
Strain gage
Rain gage
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2.1 Public Cloud Based Web Data Monitoring Service (WDMS)
The heart of the online structural monitoring instrumentation system is a Public Cloud Based Web Data
Monitoring Service offered by Encardio-rite for retrieving data from the ESDL-30 SDI-12 data logger, archiving
the data in a SQL database, processing the data and presenting the processed data in tabular and most
suitable graphical forms for easy interpretation of the logged data. The tables and graphs related to any site or
sites can be accessed by authorized personnel who can login to their site using the supplied login ID and access
password from anywhere in the world over the internet. No special software is needed for accessing the user
sites as the information can be viewed using most standard and popular web browsers like Microsoft Internet
Explorer, Mozilla Firefox, Google Chrome etc.
Data from Encardio-rite cloud based web monitoring service can be accessed from just about any type of device
that supports a standard web browser like a desktop or laptop PC, Tablet, smart phone or most other mobile
computing devices.
A graphic like a map, ground plan or a photograph is put on the opening screen marked with position of installed
sensor/sensors represented as square dots. As soon as the mouse pointer is brought over any sensor location
the corresponding sensor details like sensor identification Tag, last recorded sensor reading, and the values of
the programmed alert levels pop up in a box. If any one of the alarm level is exceeded the sensor location turns
to a red dot. Clicking the pop up table with the mouse brings up an associated data window where the sensor
data can be seen either as a table or as a graph.
CLOUD WDMS SERVER
INTERNET
ESDL-30 DATALOGGER WITH GSM/GPRS MODEM FOR
SENSORS WITH SDI INTERFACE
CELLULAR PHONE
NETWORK
MEMS TILT METERMEMS IPI SENSORS
VW PIEZOMETER
BOREHOLE EXTENSOMETER
CENTRE HOLE LOAD CELL
REMOTE USER PC/lLAPTOP
RAIN GAGE
ESVI-01-01ESVI-01-01 ESBI-10ESVI-01-01/ESVI-10VB ESGI-10
VW CRACK METER STRAIN GAGES
ESVI-01-04
Tilt meter installed on a structure (in shade). Temperature variation observed during different times of day and in different seasons
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Site administrators can set two alarm limits which are generally considered as “alert level” and “evacuate level”.
Other users can only view the data and alarm status but cannot make any changes.
The WDMS can also be programmed to send SMS alert messages or e-mail to selected users as soon as any
sensor data crosses its predefined alarm levels, either while going above or going below the alarm level. It can
also be programmed to send the health status of the system to selected users.
The web browser interface is very simple to use and intuitive. Any user who is only interested in viewing the data
and reports will take just a few minutes to get familiar with the operation of the system.
Encardio-rite cloud services work on a rental model. User has to pay a small setup fee for first time and then a
monthly rental has to be paid for accessing the data over the cloud as long as required.
NOTE: Data retrieval is also possible by directly downloading it on a laptop.
3 STRUCTURAL SURVEY
Encardio-rite group of companies and Moniterra group of affiliated companies are associated together to offer a
complete solution for safety monitoring. With our combined experience in online structural surveys and
monitoring, we are today one of the most formidable companies in this field.
3.1 Laser scanning/BIM
Laser scanning is an advance method of surveying and
conducting geometric documentation of buildings,
architectural and archaeological monuments,
engineering projects (such as tunnels, bridges, dams,
etc.) or other construction works and objects which
require a high degree of analysis, are difficult to reach
or gain access to, or are not to be touched.
It is based on exceptionally dense mapping of 3D
coordinates of the points on the surface that is to be
surveyed, taken at speeds ranging from a few thousand
up to a million points per second. Depending on the
object (size, shape, desired accuracy), laser scanning
may be airborne or terrestrial, static or mobile,
autonomous or in combination with other standard
topographic methods.
Completion of the fieldwork results in a geo-referenced point cloud which, due to its great density and its ability
to bear information on the reflectivity and/or the color of each point, comes close to the term, “virtual reality”.
Crack meter installed on structure (without shade). Temperature variation observed during different times of day and in different seasons
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Depending on the case and on the user’s needs, horizontal,
vertical or diagonal sections, aspects, images, videos,
orthophotographes, surface expansions, interval curves, 3D
models, determination of distortion as well as a number of other
analysis derived from the scanner’s operations in the non-visible
spectrum, can be produced.
To summarize, the results of laser scanning gives us:
Surveying of current state and of «as constructed» state
Virtual reality creations; Virtual tour videos
Geometric documentation of structure
Quantitative calculation
Inspection of free passage space – determination of
bottlenecks
Creation of 2D & 3D products (sections, facets, 3D models,
etc.)
Identification of deformations – discrepancies
Few application areas where laser scanning is an efficient survey method to reduce costs giving a fast, reliable and inexpensive 3D survey:
Multistory and historical buildings; Foundations
Dams, Tunnels, Bridges and overpasses, Rail/Road Projects; Walls, Pylons, etc.
Landslides and Sloping ; Earthquake-prone regions
3.2 Aerial Mapping using Unmanned Aerial Vehicles (UAV/Drone)
Inspection of huge and complex structures like buildings,
monuments, engineering projects (such as tunnels,
bridges, dams, etc.) requires high degree of analysis but
at times are difficult to reach or gain access to. Use of
Unmanned Aerial Vehicles (UAV)/Drones is best suited
for such applications.
UAVs/Drones are unmanned and remotely-piloted
aircrafts that follow a pre-programmed path for takeoff,
flight and landing. These aircrafts are equipped with
HD/IR/Thermal cameras that compute aerial images and
videos over a defined area at specified height. Using
UAVs/drones to video, model and scan for cracks, erosion, corrosion and defects in areas that would otherwise
require the inspector to climb, repel, hang from a rope/harness or erect scaffolding is obviously a safer, faster
and smarter choice. Large sites and engineering projects necessitates expensive ground based surveys or
aerial photogrammetry. Also, as the development occurs, managers have difficulty maintaining a true picture of
the site. With UAV-based mapping at regular intervals, this information gap can be closed.
Results from UAV/drone are in following
forms:
Photos & Orthophotos
Mesh 3D Models & Texture 3D
Models
Drawings
Videos - Presentations
Contour maps
Slope maps
Area - Volumetric calculations
Drone
Photos & Orthophotos
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3.3 Automatic deformation monitoring system (ATS)
The Real Time 3D deformation monitoring system is a systematic tracking of any alteration that may take place
in the shape or dimension of structure as a result of stress, load, aging etc. It also monitors the lateral and
vertical movement of existing structure which is affected during construction/excavation period.
The deformation monitoring system consists of high accuracy automatic total stations (ATS) that have the ability
of auto target recognition (without any human interference). Each ATS has a dedicated control box that includes
a computer running special software. This control box manages the total station and schedules the frequency of
the measurements, the addition or subtraction of monitor benchmarks, the filters of acceptance or repetition of
each measurement, the atmospheric corrections in distance measurements, the calculation and repositioning of
the total station etc.
The whole system can be controlled/re-configured remotely after installation at site. The on-site system
transmits the collected raw data to a remote server/computer via GPRS/GPS. Raw data is processed into
meaningful results by specialised software. The system has the facility of alert notifications through sms, email
to authorized team for any result exceeding present alarm and critical levels.
The system provides an accurate, continuous, real time data, eliminating any human error/delay in manual data.
The raw data is processed, analyzed and the result is majorly used for predictive maintenance, alarming for
safety. Few applications are:
Multistory and historical buildings; Foundations
Dams, Tunnels, Bridges and overpasses, Roads
Landslides and Sloping ; Earthquake-prone regions
Texture 3D Modelling Mesh 3D modelling
Texture 3D Modelling Video
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4 REFERENCE GUIDELINES FOR BUILDING DAMAGE CLASSIFICATION
Classification of building damage as summarized from Burland et al, 1977 by Boscardin and Cording 1989.
Building damage classification
Approximate. equivalent ground settlements
and slopes (after Rankin 1988)
Risk
category
Description of
degree of damage
Approximate. crack width
(mm)/number of cracks
Max. slope of ground Max settlement of
building (mm)
1 Negligible 0.1 to 1 <1:500 <10
2 Slight 1 to 5 1:500 to 1:200 10 to 50
3 Moderate 5 to 15/no. of cracks > 3 1:200 to 1:50 50 to 75
4 Severe 15 to 25/also on no. of cracks 1:200 to 1:50 >75
5 Very severe > 25 /also on number of cracks >1:50 >75
5 CONCLUSION
The data observed from the structural instrumentation described above plays a vital role in safeguarding existing
buildings and other structures, providing verification of design assumptions, manage the construction in a safe
and controlled manner and monitoring long term behaviour. The instruments used and the manpower deployed
for installation, monitoring and maintenance of instruments have therefore to be top quality and reliable.
Encardio-rite Group of Companies with an experience in manufacturing and monitoring of almost half a century,
are one of the best service provider in the field.
Revision # 03 September 2016